The Bioassay Core will provide biochemical assay and genotyping services for the individual projects within the Program Project. Biochemical assays that will be performed include analyses in plasma and urine for human and rat samples. The following assays will be performed: Plasma renin activity, aldosterone, angiotensin II, cortisol, corticosterone, ACTH, nitrite, nitrate, 8-isoprostane, TEARS, antioxidant capacity, hydrogen peroxide, norepinephrine, epinephrine, albumin, electrolytes, creatinine, total cholesterol, HDL, LDL, triglycerides, glucose, insulin, cystatin C, tetrahydrobiopterin, leptin, and transforming growth factor beta. Techniques will include radioimmunoassay, radioenzymatic assay, HPLC, ELISA, colorimetric, and ionselective electrodes. Genotyping of tagging single nucleotide polymorphisms of the genes of GCCR, CRHR1, p22phox, and EC-SOD will be performed for Project 2. Genotyping of the C-521T polymorphism of the angiotensin II receptor type 1 gene will be performed for Project 1. Genotyping services will be also performed for Project 3 and 4 using the tail snip DMA of the transgenic rats of the ETB receptor deficient rat and endothelial ET knockout mice. The extracted DMA will be genotyped to determine whether the rats are wildtype, heterozygous, or homozygous for the ETB receptor gene and whether the mice are wild-type, heterozygous, or homozygous for the ET gene. The core will also provide resources for development of additional assays as needed by individual investigators. The core will assure assay quality control through validation procedures.